Small Form-factor Pluggable (SFP) units represent one example of standardized hot-pluggable transceiving units. SFP units are standardized units adapted to be inserted within a chassis of a hosting unit. A suite of specifications, produced by the SFF (Small Form Factor) Committee, describe the size of the SFP unit, so as to ensure that all SFP compliant units may be inserted smoothly within one same chassis, i.e. inside cages, ganged cages, superposed cages and belly-to-belly cages. Specifications for SFP units are available at the SFF Committee website.
SFP units may be used with various types of exterior connectors, such as coaxial connectors, optical connectors, RJ45 connectors and various other types of electrical connectors. In general, an SFP unit allows connection between an external apparatus, via a front connector of one of the aforementioned types, and internal components of a hosting unit, for example a motherboard, a card or a backplane leading to further components, via a back interface of the SFP unit. Specification no INF-8074i Rev 1.0, entitled “SFP (Small Form-factor Pluggable) Transceiver, dated May 12, 2001, generally describes sizes, mechanical interfaces, electrical interfaces and identification of SFP units.
The SFF Committee also produced specification no SFF-8431 Rev. 4.1, “Enhanced Small Form-factor Pluggable Module SFP+”, dated Jul. 6, 2010. This document, which reflects an evolution of the INF-8074i specification, defines, inter alia, high speed electrical interface specifications for 10 Gigabit per second SFP+ modules and hosts, and testing procedures. The term “SFP+” designates an evolution of SFP specifications.
INF-8074i and SFF-8431 do not generally address internal features and functions of SFP devices. In terms of internal features, they simply define identification information to describe SFP devices' capabilities, supported interfaces, manufacturer, and the like. As a result, conventional SFP devices merely provide connection means between external apparatuses and components of a hosting unit, the hosting unit in turn exchanging signals with external apparatuses via SFP devices.
Recently, SFP units with internal features and functions providing signal processing capabilities have appeared. For instance, some SFP units now include signal re-clocking, signal reshaping or reconditioning, signals combination or separation, signal monitoring, etc.
In the field of video transport, advances have been made recently for transporting the payload of a video signal into Internet Protocol (IP) packets (e.g. Serial Digital Interface (SDI) video payloads encapsulated into IP packets). Furthermore, an SFP unit can be adapted to receive the IP flows transporting the video payloads from a downstream equipment, and to transmit the IP flows to a hosting unit (e.g. a switch or a router) with or without processing the video payloads of the IP flows. The switch or router further forwards the IP flows to an upstream equipment.
One issue with the transport of video IP flows on an IP networking infrastructure is that video IP flows generally require a subsequent amount of bandwidth (which can lead to network congestion) and are very sensitive to delays. The currently deployed IP based video distribution infrastructures do not always make usage of the available bandwidth in an optimized manner.
For instance, a switch (or a router) receives a plurality of video IP flows simultaneously from a plurality of input ports, where some of the input ports are adapted for insertion of an SFP unit. The router forwards the video IP flows received from the plurality of input ports to an upstream link via an output port. Due to internal processing of the received IP flows by the switch, the switch is not capable of operating at a full capacity of the upstream link. The switch is only capable of operating at a maximum capacity representing a percentage (e.g. roughly 80%) of the full capacity of the upstream link. For example, the full capacity of the upstream link is 40 Gigabits per second. The switch is only capable of forwarding the received IP flows to the upstream link via its output port at a maximal rate of roughly 32 Gigabits per second. Therefore, there is a need for new techniques allowing a better usage of the capacity of the upstream link.
More specifically, there is a need for a standardized hot-pluggable transceiving unit, a hosting unit and a method for applying delays based on port positions, in order to improve the forwarding capacity of the hosting unit.